Using controlled clinical trials, this project studies combined modality treatment (surgery, radiation, chemotherapy, immunotherapy) in childhood acute leukemia and solid tumors. Specific investigators are directed at problems of hematologic and microbiologic supportive care in patients undergoing intensive chemotherapy. Studies of the immune response, tumor immunology, and immunotherapy using BCG, other immune adjuvants and tumor cell vaccines are emphasized. Investigations of viral oncogenesis using the tools of molecular biology are also underway.